[PATCH] parser: fix parsing of messages with empty subjects

[Stephen Finucane]

On Sat, 2017-07-08 at 12:32 +1000, Daniel Axtens wrote:
> Stephen Finucane <stephen at that.guru> writes:
> 
> > On Sat, 2017-07-08 at 00:24 +1000, Daniel Axtens wrote:
> > > The fuzz fixups made the test too strict ("if not subject" rather than
> > > "if subject is None") in an attempt to catch broken subject headers.
> > > This broke parsing of messages with an empty subject.
> > > 
> > > Fix it and add a test.
> > > 
> > > Signed-off-by: Daniel Axtens <dja at axtens.net>
> > 
> > Is a mail with an empty subject really valid for our use cases?
> 
> You can get a valid patch with an empty subject. It's dumb and people
> shouldn't do it, but it is not broken per se.

That's fair.

Reviewed-by: Stephen Finucane <stephen at that.guru>

...and applied.